Cook made the announcement Sunday on Twitter, saying that its design, engineering, packaging and operations teams are working with suppliers to get the shield made and shipped.

The first shipment was delivered to a Santa Clara, California, hospital last week. The shields are fully adjustable and assemble in under two minutes, he said, adding that Apple plans to ship over a million this week and another million weekly after that.

Apple plans to quickly expand shipping of the shields beyond the U.S., the executive said. Apple has shuttered all 458 of its retail stores outside of China to curb the spread of the Covid-19 pandemic and is requiring its engineers and designers to work from home.